A hybrid vehicle may be propelled by an engine and/or an electric machine. In such a vehicle, there can be powertrain modes that enable the vehicle to be propelled using only the electric machine with the transmission input clutch(es) open, allowing the engine to be stationary. Such vehicles may in some examples include a park-pawl, comprising a device fitted to the vehicle's transmission in order to lock up the transmission. Specifically, the parking pawl locks the transmission's output shaft by engaging a pawl or pin that engages a notched wheel on the output shaft, thus stopping it and the driven wheels from rotating. To disengage the parking pawl typically requires engine operation. However, for a hybrid vehicle that offers functions such as silent drive away using an electric-only mode of operation, it may not be desirable to start the engine to release park, and then turn the engine off again. Such actions may be inefficient, and may be counterintuitive to the vehicle operator.
The inventors have recognized the above-mentioned issues, and have developed systems and methods to at least partially address them. In one example, a method comprises engaging a parking pawl to an output shaft of a dual clutch transmission in response to a request to enter a vehicle into a parked state; and disengaging the parking pawl via rotating an engine via an integrated starter/generator in response to a request to propel the vehicle solely via power of an electric machine positioned downstream of the dual clutch transmission.
In one example, such a method includes ceasing engine rotation in response to an indication that the parking pawl is released. In this way, a hybrid vehicle may be enabled to launch the vehicle in an electric-only mode of operation, without undesirably activating the engine in a fueled mode of operation, and then deactivating the engine. By avoiding fueled engine operation to release the parking pawl, fuel efficiency may be increased, undesired emissions may be reduced, and customer satisfaction may be improved.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.